This invention relates to a drive controlling device of an electric motor-driven vehicle such as an electric motor-driven golf car or the like ands more particularly to an arrangement for protecting against inadvertent application of power due to a failure in the accelerator control system.
In recent years, there have been proposed a wide variety of electric motor powered vehicles for a variety of purposes. For example, electrically powered golf cars are widely used in golf courses. In such applications controls have been incorporated for accommodating the various terrains over which these vehicles are operated. As a specific example golf carts frequently employ sensors for determining the slope of the ground on which the cart is operating to provide the appropriate power to compensate for changes in grade. An example of such a control arrangement is shown in Japanese Published application JP-A-Hei 10-309005.
In this arrangement, the electric motor-driven golf car, like an ordinary road vehicle, is provided with an accelerator pedal and a brake pedal for operation by the driver to control running of the golf car. Specifically, operation of the accelerator pedal by a driver, for example, is transmitted to an accelerator switch and an accelerator sensor connected to a controller that appropriately controls the drive of a shunt-wound type motor of the vehicle.
However, the electric motor-driven golf car of this type is often subjected to irregular shocks from outside due to particularity of its use. These shocks may be caused from various unique conditions such as the loading and unloading of golf bags or operation over rough ground surfaces. It is not uncommon for these shocks to cause breakage of wire of the accelerator sensor resulting in an abnormality of its output. In such a case, the motor controller fails to read the actual position of the accelerator pedal operated by the driver and the golf car may run against the driver's intention.
It is, therefore, a principal object of this invention to provide in arrangement for insuring against undesired operation in the event of a failure in the accelerator control mechanism.